package com.atguigu.day09;

import com.atguigu.bean.WaterSensor;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.annotation.DataTypeHint;
import org.apache.flink.table.annotation.FunctionHint;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.table.functions.AggregateFunction;
import org.apache.flink.table.functions.TableFunction;
import org.apache.flink.types.Row;

import static org.apache.flink.table.api.Expressions.$;
import static org.apache.flink.table.api.Expressions.call;

public class Flink05_UDF_AggFun {
    public static void main(String[] args) throws Exception {
        //1.获取流的执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        env.setParallelism(1);

        //2.从端口读取数据
        SingleOutputStreamOperator<WaterSensor> waterSensorDStream = env.socketTextStream("localhost", 9999)
                .map(new MapFunction<String, WaterSensor>() {
                    @Override
                    public WaterSensor map(String value) throws Exception {
                        String[] split = value.split(",");
                        return new WaterSensor(split[0], Long.parseLong(split[1]), Integer.parseInt(split[2]));
                    }
                });
        //3.获取表的执行环境
        StreamTableEnvironment tableEnv = StreamTableEnvironment.create(env);

        //4.将流转为表
        Table table = tableEnv.fromDataStream(waterSensorDStream);

        //不注册直接使用函数
//        table
//                .groupBy($("id"))
//                .select($("id"),call(MyUDAF.class, $("vc")))
//                .execute().print();

        //注册自定义函数
        tableEnv.createTemporarySystemFunction("myUDAF", MyUDAF.class);

        //先注册再使用
//        table
//                .groupBy($("id"))
//                .select($("id"),call("myUDAF", $("vc")))
//                .execute().print();

        tableEnv.executeSql("select id,myUDAF(vc) from "+table+" group by id").print();

        env.execute();

    }

    //TODO 自定义一个聚合函数，多进一出，求相同id的VC平均值
    public static class MyACC{
        public Integer vcSum;
        public Integer count;
    }

    public static class MyUDAF extends AggregateFunction<Double,MyACC>{

        @Override
        public MyACC createAccumulator() {
            MyACC myACC = new MyACC();
            myACC.vcSum = 0;
            myACC.count = 0;
            return myACC;
        }
        public void accumulate(MyACC acc, Integer value) {
            acc.vcSum += value;
            acc.count++;

        }
        @Override
        public Double getValue(MyACC accumulator) {
            return accumulator.vcSum*1D/accumulator.count;
        }
    }


}
